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Title: Direct single ion machining of nanopores.

The irradiation of thin insulating films by high-energy ions (374 MeV Au{sup +25} or 241 MeV I{sup +19}) was used to attempt to form nanometer-size pores through the films spontaneously. Such ions deposit a large amount of energy into the target materials ({approx}20 keV/nm), which significantly disrupts their atomic lattice and sputters material from the surfaces, and might produce nanopores for appropriate ion-material combinations. Transmission electron microscopy was used to examine the resulting ion tracks. Tracks were found in the crystalline oxides quartz, sapphire, and mica. Sapphire and mica showed ion tracks that are likely amorphous and exhibit pits 5 nm in diameter on the surface at the ion entrance and exit points. This suggests that nanopores might form in mica if the film thickness is less than {approx}10 nm. Tracks in quartz showed strain in the matrix around them. Tracks were not found in the amorphous thin films examined: 20 nm-SiN{sub x}, deposited SiOx, fused quartz (amorphous SiO{sub 2}), formvar and 3 nm-C. Other promising materials for nanopore formation were identified, including thin Au and SnO{sub 2} layers.
Authors:
; ; ;
Publication Date:
OSTI Identifier:
919651
Report Number(s):
SAND2004-5090
TRN: US200825%%260
DOE Contract Number:
AC04-94AL85000
Resource Type:
Technical Report
Research Org:
Sandia National Laboratories
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY; POROUS MATERIALS; PORE STRUCTURE; THIN FILMS; FORMVAR; IRRADIATION; MACHINING; MICA; QUARTZ; SAPPHIRE; SILICON NITRIDES; SILICON OXIDES; CARBON; GOLD; TIN OXIDES; NANOSTRUCTURES; Nanopores; Etching.; Ion bombardment.